yes, no 6x MR6 modules.
you can have MR6 + MR5 + Hau6 + Com6... or any combination. just one of each kind

and here :CE Store description
MODULES: You may also choose to add up to a maximum of Five UNIQUE ship modules to the layout. Unique means that whilst you can add up to five modules to a ship they must ALL be unique. Each slot component added will have an overall affect on the end build